a. Field of the Invention
The present invention relates generally to coverings for architectural openings such as doors, windows, and the like, and more particularly to a control system for a covering having a plurality of vertically suspended vanes linearly movable between extended and retracted positions, as well as pivotally movable between open and closed positions, to control visibility and the passage of light through the architectural opening.
b. Description of the Relevant Art
Covers for architectural openings such as doors, windows, and the like have been known in various forms for many years. One form of such covering is commonly referred to as a vertical vane covering wherein a control system suspends and is operable to selectively manipulate a plurality of vertically suspended vanes such that the vanes can be linearly moved laterally across the architectural opening to extend or retract the covering and can be pivoted about longitudinal vertical axes to open and close the vanes.
Control systems for operating vertical vane coverings typically include a headrail in which a plurality of carriers associated with each vane are mounted for lateral movement, and include internal mechanisms for pivoting the vanes about their vertical axes. The headrails vary in construction and configuration to house the various types of carriers, but typically the headrails are relatively large and rectangular in cross section to enclose the working components of the system. Many such headrails have a slot along a bottom wall through which a portion of each carrier protrudes for connection to an associated vane.
Most control systems include pull cords that are operably connected to the carriers to shift or linearly move the carriers horizontally along the headrail and across the architectural opening. Control systems also usually include a horizontally disposed tilt rod operably connected to each carrier such that rotational movement of the tilt rod about its longitudinal axis transfers corresponding movement to the carriers and subsequently to the vanes to effect pivotal movement of the vanes about their longitudinal vertical axes. The tilt rod is typically rotated by a pull cord or a tilt wand that can be grasped by an operator of the system.
Considerable attention has been given to the configuration and construction of headrails as they are readily visible in vertical vane coverings. U.S. Pat. No. 4,361,179 issued to Benthin, for example, discloses a headrail having an opening through the top thereof so as to improve the aesthetics of the headrail. The primary components of each carrier in the system are confined within the interior of the headrail and generally "C" shaped hangers associated with each carrier circumscribe the headrail so as to be in a position to support an associated vane from beneath the headrail.
Carriers in vertical vane coverings may be interconnected by a pantograph so that movement of an endmost or lead carrier causes all of the carriers to move correspondingly. One problem with prior art control systems has been the manner in which the carriers are connected to the pantograph. Typically, due to the central connection system and expansion of the pantograph upon movement of the lead carrier, the other carriers are caused to skew slightly resulting in increased friction and making them more difficult to move along the length of the tilt rod.
Another shortcoming in prior art systems which utilize pull cords to move the lead carrier is the fact that the pulleys for returning and deflecting the pull cords are normally relatively small in size thereby requiring multiple revolutions to allow significant movement of the carriers which increases system friction and imposes unnecessary wear on the system.
Another problem with prior art control systems resides in the fact that they are difficult to assemble inasmuch as the drive mechanism of the carriers associated with the vanes must be uniformly aligned and operably connected to the tilt rod so that pivotal movement of the tilt rod moves the vanes between associated and corresponding angular positions. Accordingly, if the carriers are not mounted on the tilt rod uniformly, the vanes will not be properly aligned and uniformly angularly related to the architectural opening. As will be appreciated, in order to properly align and uniformly angularly relate the vanes to the architectural opening, the carriers have to be carefully and uniformly mounted on the tilt rod, which can be a time consuming endeavor.
Still another prevailing problem with prior art control systems for vertical vane coverings resides in the fact that the vanes are suspended in spaced relationship from the bottom of the headrail thereby establishing a gap that allows undesired light to pass between the top edge of the vanes and the bottom of the headrail. While the window covering itself may adequately block the passage of light through the architectural opening, this spaced relationship of the top edge of the vanes with the headrail undesirably permits the passage of light through the gap.
Since the pull cords utilized to move the lead carrier along the length of a tilt rod apply a significant force to the lead carrier which, in turn, expands or contracts the pantograph to effect corresponding movement of the other carriers, it will be appreciated that a skewing of the lead carrier can also be a problem depending upon the spacing of the pull cords from the tilt rod on which the carriers are mounted. Skewing of the lead carrier which increases drag on the system has traditionally also been a problem in prior art systems.
As will be appreciated from the above, drag in a control system resulting from friction between the various relatively movable parts has been a drawback. Accordingly, a need exists in the art for a low friction system that is easy to operate and is more durable for extended maintenance-free operation.
Another shortcoming in many prior art systems relates to the design of the headrail. The design and configuration of the headrail, as may not be readily appreciated, can create problems for an installer of vertical vane coverings. Many headrails used in vertical vane coverings are non-symmetric in transverse cross section in order to accommodate in a compact manner the working components of the associated control system. Examples of such headrails are disclosed in U.S. Pat. No. 5,249,617 issued to Durig, U.S. Pat. No. 4,381,029 issued to Ford, et al., and U.S. Pat. No. 4,381,029 issued to Ford, et al. While such systems may compactly accept the associated components of the control system, they are many times undesirable from an installation standpoint as they can only be installed in one orientation. If a headrail is blemished or marred, for example, on an outer visible surface, it is usually deemed unusable.
It is to overcome the aforenoted shortcomings in the prior art systems that the present invention has been developed.